That photo is great — the mini 3x3 sitting on top and the penny on the corner really sell how big that thing is. It looks like a proper display piece.
Do you actually try to solve it, or is it mostly for fun? I can imagine the turns being a full-arm workout, and keeping track of the pieces at that size must be a completely different experience from a normal 3x3. Either way, nice one from your cousins — that's a memorable first big cube.